Concept of synchronized methods & code blocks

[Ashik Uzzaman]

Hi ranchers,
I m about the following concept of multithreading. I think the concept is correct but help me with explaination/codes.
The Concept :
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When locking an object through using synchronized methods we only lock the methods that r syncronized and other non-synchronized methods r as well unaccessible from other threads who want to work on the same object, until the current thread working on the object does not leave the lock of the object. If the methods r not synchronozed but only synchronized code blocks r used then the same thing is happenning,i.e. the threads have to wait for the lock.

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azaman

[Jane Griscti]

Hi Ashik,
You've got the concept right

public class X {
    int x = 10;
    public readX(){
        return x;
    }
    public synchronized writeX(int i){
         x = i;
    }
}

In the above code, <code>readX()</code> is not synchronized. It can be invoked at any time and will return whatever value of 'x' it finds without having to wait to obtain a lock on 'x'.
The <code>writeX(int i)</code> method is <code>synchronized</code>; before a thread can actually execute a write of 'x' it must first obtain the lock. So writes have to wait their turn but reads don't.
Hope that helps.
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Jane Griscti
Sun Certified Programmer for the Java� 2 Platform

[Ashik Uzzaman]

Thnx Jane! Would u see my other post related ti this one ...
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azaman